Recently, researches on automated driving techniques of automobiles have been actively conducted in various countries, and each country considers legislation to allow a vehicle (hereinafter the “vehicle” refers to an automobile) to travel on public roads in an automated driving mode. In the automated driving mode, a vehicle system automatically controls the traveling of the vehicle. Specifically, in the automated driving mode, the vehicle system automatically performs at least one of steering control (control of a traveling direction of the vehicle), brake control and accelerator control (control of braking and acceleration/deceleration of the vehicle) based on information (surrounding environment information) indicating a surrounding environment of the vehicle obtained from a sensor such as a camera or a radar (for example, a laser radar or a millimeter wave radar). On the other hand, in a manual driving mode described below, a driver controls the traveling of the vehicle as is the case of the conventional vehicles. Specifically, in the manual driving mode, the traveling of the vehicle is controlled according to the driver's operation (the steering operation, the brake operation, and the accelerator operation), and the vehicle system does not automatically perform the steering control, the brake control, and the accelerator control. Herein, the driving mode of the vehicle does not refer to concept which exists only in some vehicles but refers to concept which exists in all vehicles including a conventional vehicle not having an automated driving function and is classified according to, for example, a vehicle control method or the like.
Accordingly, it is expected in the future that a vehicle traveling in the automated driving mode (hereinafter referred to as an “automated driving vehicle” as appropriate) and a vehicle traveling in the manual driving mode (hereinafter referred to as a “manual driving vehicle” as appropriate) coexist on a public road.
As an example of an automated driving technique, JP-A-H9-277887 discloses an automatic following travel system where a following vehicle automatically follows a preceding vehicle. In the automatic following travel system, the preceding vehicle and the following vehicle each includes a lighting system, and character information for preventing another vehicle from interrupting between the preceding vehicle and the following vehicle is displayed on the lighting system of the preceding vehicle, and character information indicating that the following vehicle automatically follows the preceding vehicle is displayed on the lighting system of the following vehicle.
In an automated driving society where the automated driving vehicle and the manual driving vehicle coexist, it is expected that a vehicle mounted with an automated driving system lamp (hereinafter, referred to as an “ADS lamp”) for visually presenting information (for example, information on the automated driving mode of the vehicle) related to automated driving to a pedestrian or the like. In this case, since the pedestrian can grasp a current situation of the automated driving vehicle by visually recognizing the ADS lamp, the pedestrian's anxiety to the automated driving vehicle can be reduced. Meanwhile, it is assumed that the visibility of the ADS lamp from an object (such as a pedestrian) decreases according to a predetermined condition. Accordingly, in the upcoming automated driving society, there is room for further consideration on the visibility of the ADS lamp.